The invention relates to the field of airborne biological pathogen detection. More specifically the invention is directed to a sampling device and particle detector for the detection of air borne particles that have sizes consistent with certain hazardous biological pathogens that can be used as biological warfare agents. The invention also relates to a integrated system of sampling devices described herein that is useful for the detection of potential airborne biological pathogens.
There is a concern among public officials in the United States that certain populations when grouped in large numbers or while attending public events are vulnerable to terrorist attack and, more particularly, vulnerable to attack by the use of air borne biological and chemical agents. For example, events of concern include civic events such as parades, national and local celebrations, sporting events, marches and political rallies that involve the gathering of large numbers of individuals. A further concern among public health officials is the dispersal of such agents in a large indoor environment such as subway systems, indoor arenas, shopping malls, office buildings and large banquet facilities. A further concern among both public heath and security officials is the targeted release of biological agents in the proximity of certain government buildings such as, the FBI, the Pentagon, the White House, the Capitol, or military installations and naval vessels. Any of these locations make attractive targets for terrorists and the costs associated with installing and monitoring detection devices in such targeted geographical regions may be justified by the threat.
Although effective delivery methods for airborne biological agents remain a logistical problem for terrorists, a number of delivery methods are considered viable. Currently, anticipated manners to deliver such biological agents into the air include aerosols from either aircraft or ground based mobile systems. It is generally acknowledged that to be an effective biological weapon, airborne pathogens must be dispersed as fine-particles between 1-20 microns and preferably, between 1 and 5 microns in size. Infection with aerosolized or lyophilized agents like Bacillus anthraces, small pox, brucellosis, tularemia, and Venezuelan Equine Encephalitis (xe2x80x9cVEExe2x80x9d), usually requires deep inspiration of infectious dose, best achieved by small particle size of about 1 to 5 microns. The aerosolized delivery of biological agents can be achieved by rather xe2x80x9clow-techxe2x80x9d aerosolization methods including agricultural crop-dusters; aerosol generators on small boats, trucks, or cars; backpack sprayers; and even hand size atomizers, such as those used for perfume applications.
Because biological attacks typically do not manifest symptoms until some time after the first exposure of the virulent agent, an early and accurate identification of the agent is of critical importance. The rapid identification of the agent may allow authorities to quickly implement a measured remedial response, which may involve a range of actions including evacuations, quarantines, educational and information campaigns, and the administration of medical treatment. Early detection of a biological agent in the environment allows for early specific treatment and time during which prophylaxis would be effective. The ability to accurately detect the presence of such agents without false positives is particularly important to the public health of civilians and government officials. An early, rapid and accurate detection is also a paramount concern among law enforcement officials. If such law enforcement offices quickly perceive and understand that a biological attack is underway, the chances of apprehending the perpetrators is also increased.
The present invention involves a sampling and detection device for airborne particles that includes a dual air intake and filtering system for the parallel sampling of ambient air. Air first flows past a particle detectors that provide a signal in response to the presence and size of particles entrained in the air. The particle detectors are calibrated to be particularly sensitive to those signals. In a preferred embodiment the particle detector comprises a LED and photodetector array that detects the presence of light that is reflected from particles entrained in the air stream. Very large particles are prevented from entering the air intake by a mesh screen. The signal from the photodetector is transmitted to a microprocessor, stored and compared to signals from known circumstances. For example, the duration and intensity of a pulse from a photodetector is indicative of the respective size of the particle. In the event that the signal from the microprocessor is similar to a known signal, the microprocessor will implement a communications program that will cause the data to be transmitted over a wireless link. In an alternative embodiment the microprocessor will process the signal and seek a predetermined increase in the signal strength and from a baseline. In the event that the threshold is surpassed, the communications program is implemented and the data from the storage is communicated over a transmission link. The sampling stations contain two parallel filters across the downstream of the particle detectors for the capture of particles. A plurality of filters are provided at the location and the filters are automatically sequentially introduced into the airstream at predetermined time intervals. As filters are removed from the airstream they are sealed, secured and labeled with the time and other information relating to the location of the sample.
In a preferred embodiment of the invention, in addition to the data relating to particle size, additional information is also that identifies the sampling station, the location of the station, ambient weather condition and the time that the data was recorded. Thus in a preferred embodiment the sampling station includes a global positioning system, a clock, weather monitoring equipment. Data from each of these components is transmitted to a remote location.
In yet a further embodiment a number of sampling devices in a particular geographic locations are continuously monitored from a remote location. Data may be automatically transmitted at predetermined time intervals, regardless of the input from the photodetector and read by a technician. Thus data is transmitted to a remote command unit location for analysis and processing. For example the data from the photodetector can be correlated with wind speed and the time of the sample. Later, either at predetermined time intervals, or, for example, in response to a signal from the processor that indicated that the photodetector signal exceeded a predetermined threshold, the filters for the corresponding time interval are collected from the sampling station and analyzed.
The invention further provides an integrated mobile system for the detection of airborne biological pathogens comprising a plurality of the aforementioned sampling devices at various geographic locations, the sampling device capable of communication, preferably by a wireless means, with a central command unit which further comprises a mobile laboratory equipped for the qualitative and rapid analysis of pre-selected target agents.